#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b, k;
  cin >> a >> b >> k;
  if (a == b) {
    cout << "1.";
    while (k--) cout << '0';
    cout << endl;
    return 0;
  }
  cout << "0.";
  while (k > 1) {
    a *= 10;
    cout << a / b;
    a %= b;
    k--;
  }
  a *= 10;
  int last = a / b;
  a %= b;
  a *= 10;
  int lala = a / b;
  if (lala <= 4) {
    cout << last << endl;
  } else {
    cout << last + 1 << endl;
  }
}
